Tan or yellow leaf spot
Area of impact: Leaf
Description: Small yellow-brown spots that grow into larger oval-shaped brown blotches. As the lesions merge portions of the leaf yellow and die. Small dark brown spots may be found at the center of the lesion.
Pathogen involved: Pyrenophora tritici-repentis (a fungus)
Timing/Conditions: Most likely in the spring after extended periods of leaf wetness.
Contributing factors: The fungus oversummers in infested wheat stubble. Shortened or continuous wheat rotations and reduced tillage contribute to the disease.
Management practices: Rotate out of wheat for two or more years; avoid excessively dense lush stands and bury infested wheat stubble.